One commonly used material in the fabrication of integrated circuitry is silicon dioxide. Such might be utilized as essentially 100% pure, or in combination with other materials, including property-modifying dopants. Accordingly, silicon dioxide might be utilized as a mixture with other materials in forming a layer or layers and may or may not constitute a majority of the given layer. Exemplary materials are borophosphosilicate glass (BPSG), phosphosilicate glass (PSG), and borosilicate glass (BSG). Typically, such materials have anywhere from 1% to 4% atomic concentration of each of boron and/or phosphorus atoms, although atomic percent concentrations in excess of 5% have also been used.
As semiconductor devices continue to shrink geometrically, such has had a tendency to result in greater shrinkage in the horizontal dimension than in the vertical dimension. In some instances, the vertical dimension increases. Regardless, increased aspect ratios (height to width) of the devices result, making it increasingly important to develop processes that enable dielectric and other materials to fill high aspect or increasing aspect ratio trenches, vias and other steps or structures. A typical dielectric material of choice has been doped and/or undoped silicon dioxide comprising materials, for example those described above. Dopants such as boron and phosphorus can facilitate a reflowing of the deposited layer at a higher temperature to facilitate more completely filling openings on a substrate. Various reactant precursors can be utilized in forming silicon dioxide layers, for example the silanols disclosed in U.S. Pat. No. 6,300,219.